UIAA Rope Standards of the International Climbing and Mountaineering Federation

The full name of UIAA is: Union Internationale des Associations d'Alpinisme (International Mountaineering and Climbing Federation). It is an internationally recognized authoritative organization that sets standards for climbing equipment. The UIAA mark indicates that the product has passed tests specified by the UIAA and meets the standards set by them.

The CE mark is more commonly seen than the UIAA mark because its scope is not limited to climbing equipment. CE indicates that the product is fit for its intended use.

Climbing equipment is classified under CE as: personal protective equipment of complex design (PPE). CE stipulates that all PPE must be able to provide sufficient protection to save the user from potentially fatal risks; it must be easy and comfortable to wear, and must be compatible with other PPE used in conjunction with it.

Besides UIAA and CE, there is a newer set of "European Standards" – European Norms, abbreviated as ENs – that are gradually being accepted by many countries worldwide as an indicator of product suitability. For climbing equipment, although most EN standards are based on UIAA standards, they are more strictly defined and more recent. The ENs set additional requirements for how climbing ropes should be constructed and the performance level ropes must achieve under controlled conditions.

Standards for Dynamic Ropes set by UIAA and ENs

1. A low-impact-force rope means that under a test load of 80 kg and a fall factor of 2, the maximum impact force for a single rope must not exceed 1200 daN. Under a test load of 55 kg and a fall factor of 2, the maximum impact force for a half/twin rope must not exceed 800 daN. *1 daN = 1.02 kg

2. Under a load of 80 kg, a single rope must withstand at least 5 falls with a fall factor of 2. (The load for half ropes is 55 kg).

3. Under a load of 80 kg, the static elongation of a single rope must not exceed 8%. Under a load of 55 kg, the static elongation of a half rope must not exceed 10%.

4. When pulling a 2-meter long rope through a testing machine 5 times, the sheath slippage must not exceed 40 cm.

5. The rope must be marked with the rope type (single/half/twin), manufacturer, and the CE certification mark.

Impact Force

When a leader falls, the force of gravity (g) creates kinetic energy from the fall. The longer the fall distance, the greater the kinetic energy. When the fall is arrested by the belayer (before this, the rope is not under load), the kinetic energy from the fall must be converted into another form of energy and released (since the climber is no longer falling); this is the potential energy stored in the stretched rope.

The "maximum impact force" marked on a new rope is the value measured during its first UIAA test fall with a fall factor of 2. Repeated falls cause the rope to gradually lose its elasticity and its ability to absorb kinetic energy decreases, therefore the impact force increases with subsequent falls. After each lead fall, it's best to let the rope rest for 5 minutes, allowing the core time to recover, to prevent shortening the rope's lifespan.

When a rope completely loses its elasticity, the internal nylon fibers will be damaged by the heat generated from falls, until eventually a fall causes it to break. (This damage may not be visible on the rope's surface).

It is recommended that lead climbers alternate the ends of the rope they use and tie in with a Figure-8 knot, as it absorbs fall forces better and is less likely to loosen than a Bowline knot.

Static Elongation

Refers to the elongation of a rope measured under a static load of 80 kg. Ropes with low static elongation (below 5%) have less elasticity and are suitable for aid climbing (a type of climbing that relies on the rope and other equipment to support the climber's weight for ascending, traversing, and descending. Canyoneering, which often uses ascenders and self-belays, can also be considered a type) but are unsuitable for most free climbing activities. Ropes with high elongation (6%-8%) are more elastic and can absorb more fall energy.

An "ideal" climbing rope would possess both "low impact force" and "low elasticity". Low impact force absorbs more fall energy; low elasticity prevents the rope from stretching too long during a fall, avoiding the risk of the leader hitting a rock or the ground. However, in practice, this is unachievable because requiring low impact force necessitates the rope stretching longer. Therefore, when selecting a rope, one can only try to find one that comes closest to the ideal, for example, if two ropes both have a static elongation of about 6%-7%, choose the one with the lower maximum impact force.

The fall factor is calculated as follows:

Fall Factor (F) = Fall distance / Length of rope between leader and belayer

PS. If a rope experiences even "one" fall with a fall factor = 2, it absolutely must not be used again.